ICQ notifies you when your friends' are on-line at any time and enables you to contact them at will.  With ICQ, you can chat, send messages, files and URL's, play games, or just hang out with your friends' while still surfing the Net.

IRC (Internet Relay Chat) is a virtual meeting place where people from all over the world can meet and talk; you'll find the whole diversity of human interests, ideas, and issues here.